Study On The Quality Improvement Of Propylene Oxide By Process Of Chlorohydrin

In recent years, with the continuous development of high-grade polyether, that is the downstream products of propylene oxide, users have further increased requirements on the quality of propylene oxide product. To improve the propylene oxide product quality, reduce production costs and increase the market competitiveness of enterprise, we analyzed production system of propylene oxide comprehensively, found the various factors affecting the propylene oxide product quality, and targeted for process adjustment and optimization of control.In the process of chlorohydrination, the ratio of the raw material and water was reasonable controlled and the quality of raw water was improved, to reduce the effects of dichloropropane on propylene oxide product quality in the saponification reaction; Chloropropanols recovery system and dichloropropane washing system were transformed to reduce the content of propylene dichloride and aldehyde in Chloropropanol liquid recovery; The circulating air system was transformed to reduce the dichloropropane formation during the Chlorohydrination reaction process. In the saponification step, it is necessary to reduce the pressure of saponification to shorten the residence time of propylene oxide and avoid the occurrence of side reactions in the saponification tower. However, the trays blockage and the presence of dichloropropane oil phase had a great impact on saponification reaction and then some projects were implemented such as the saponification tower rinse water system adjustment, process optimization control and pickling liquid chlorine propanol recycling; In distillation processes, some measures were adopted for considering separation and recovery of propylene oxide and aldehydes such as the adding the salt water and then heating up in the crude distillation tower bottoms, optimization of process control of distillation system. After transformation, the total aldehyde content was down from 0.0087% to 0.0108% in the propylene oxide product. Moisture content was reduced from 0.018% to 0.026% under high load conditions. Superior product rate reached 100%, according to the current propylene oxide product standards. To further enhance the propylene oxide product quality and reach the superior product level of new industry standards, it's necessary to transform the technology of the distillation system continually and add the removal of light component tower and the removal of aldehyde device.The research results have some reference and benefits for the direct oxidation method and combined method of propylene oxide production process to improve product quality of propylene oxide.